The Changing Nature of River Restoration. Ben Smith, King s College London Professor Nick Clifford, King s College London

Transcription

1 The Changing Nature of River Restoration Ben Smith, King s College London Professor Nick Clifford, King s College London

2 Background Restoration project on the River Brent. Wharton (28) Rapid rise in restoration over last 25 years as value of river ecosystems recognised. Perceptions of rivers change and this influences what we want from them and the drivers for restoration projects

3 What can we learn? We know monitoring and PPA aren t as widespread as we d like. How do you combine data which already exists to enhance understanding of restoration projects? Objective was to use existing datasets to explore: - How have drivers of restoration changed and what effect has legislation had? - Are there patterns to the physical characteristics of restoration sites (energy, geology etc)?

4 Methods Looked at projects in the RRC s project database (NRRI) for primary motivation and assessed change over time where dates available. Google Scholar keyword searches to examine changes in emphasis in the literature e.g. river restoration + fisheries vs river restoration + habitat Comparison of terminology: differences between river and stream, or restoration, rehabilitation and enhancement Used a combination of RHS data, and GIS data such as geology, to gain information about the project sites.

5 Overview of UK river restoration 22 Geology of Projects 27 Sedimentary 589 Chalk Hard Rocks Mostly lowland Large number around London Relatively large proportion on Chalk

6 Energy Conditions Projects according to Jeffers (1998) energy and location classification Dominated by lowland sites Moderate in terms of energy

7 Drivers of restoration Both NRRI and the literature are dominated by habitat/ecological reasons for restoration. Similar results found for Scotland and U.S (Gilvear et al. 21, Bernhardt et al. 25).

8 Cumulative Number of Projects Number of Articles Changes over time Year Time Period River restoration River rehabilitation River enhancement Stream restoration Stream rehabilitation Stream enhancement Total Large increase both in numbers of project in the NRRI (under-representation) and in references in the literature.

9 Number of Articles % of projects Changes over time Decade Habitat Fisheries Bank Erosion Flood Defence Habitat Fish Ecological Ecosystem Flood Bank Erosion Decline in importance of projects for flood defence and bank protection. Rise of fisheries and habitat projects (most ecological categories) Rise of ecological and ecosystem based restoration articles Time Period

10 % of projects % of articles What effect WFD? Pre-WFD Post-WFD There is a significant difference (p =.2) between pre and post-wfd periods, with a more ecological focus clear. Keyword Difficult to disentangle from broader changes, but WFD ecological emphasis make it a significant contributing factor Motivation Pre-WFD Post-WFD

11 Number of Articles Number of Articles Differences in terminology Time Period Time Period River Restoration Stream restoration Ecological not dominant as a category in stream searches could reflect geographical differences in terminology. Enhancement searches show no ecological increase.

12 Conclusions Different datasets can be combined to support a better understanding of river restoration. Shift towards ecologically-focused restoration confirmed, and fits with the WFD. Further work looking at land-use, catchment types and sensitivity to climate change Broadscale analysis doesn t replace monitoring but can be complementary.

13 Thanks for listening!

14 14 TH ANNUAL NETWORK CONFERENCE Scaling up our Aspirations for River Restoration and Management The RRC would like to thank the sponsors of the RRC Annual Conference 213 who support discounted places